BACILLUS OF TUBERCULOSIS. 283 



Infection by Ingestion of Milk and Meat. Phthisi- 

 cal sputum, however, is not held responsible for the 

 occurrence of all human tuberculosis. Milk also 

 serves as a conveyer of infection, whether it be the milk 

 of nursing mothers suffering from consumption or the 

 milk of tuberculous cows. The transmission of tubercle 

 bacilli in the milk of tuberculous individuals has only 

 been indirectly established in human beings, but in 

 cow's milk it has been abundantly proved. Formerly 

 it was thought that in order to produce infection by 

 milk there must be local tubercular affection of the 

 udder; but it is known now that tubercle bacilli may 

 be found in the milk when an internal organ is infected 

 and when careful search fails to detect any udder dis- 

 ease. So that the milk of every cow which has any 

 internal tubercular infection must be considered as pos- 

 sibly containing tubercle bacilli. Rabinowitsch and 

 Kempner proved beyond all question that not only the 

 milk of tubercular cattle which showed no appreciable 

 udder disease, but also those in which tuberculosis was 

 only detected through tuberculin, frequently contained 

 tubercle bacilli. Different observers have found tubercle 

 bacilli in the milk of from 20 to 60 per cent, of tuber- 

 culous cows. When we consider the prevalence of tuber- 

 culosis among cattle we can readily realize, if the 

 bovine bacillus readily infects human beings, the 

 danger to which children are exposed from this source 

 of infection. Thus, taking the abattoir statistics of 

 various countries, we find that in Prussia 8.3 per cent, 

 of the cattle slaughtered were tuberculous; in Dresden, 

 14.4 per cent.; in London, 25 per cent.; in Berlin, 12 

 per cent.; in New York, about 7 per cent. Another 

 possible source of infection in intestinal tuberculosis is 



